The present invention relates to an apparatus for forming powder and granular refractory lining materials on inside walls of a container to be lined (herein called simply as a container) using a vibration-pressing mold which is allowed to sink-down freely in a stabilized state.
The term "container" used herein means any container in which molten metal, such as molten pig iron and molten steel is contained or is made to flow, and specifically it means a tapping trough for molten pig iron or steel, a tundish for continuous casting, a ladle and a furnace or vessel for degasing. The term "powder and granular refractory materials" used herein means any powder and granular refractory materials which have a controlled particle size, mixed, with water and binder usable for casting, ramming or spraying but they must have inherent or given thixotropic property.
The thixotropic property of refractory materials means the nature that when the refractory materials are given vibration they fluidizes as like slurry, and when the vibration is stopped they solidify, and this property can be developed by grain size distribution adjustment, control of water content, addition of peptizer etc.
As for a method for lining a powder and granular refractory mix having the thixotropic property onto the inside wall of a metallurgical container, a method has been proposed in which the formation is done under vibration and pressure using a forming mold. More specifically, a refractory mix is charged in the container and a forming mold having a weight on its top is placed on the mix and allowed to sink-down with vibration, thereby the refractory mix which is fluidized like slurry in the space between the container and the mold is vibrated upward to fill the space, and then the vibration is stopped and the mold is taken out from the container to finish the lining on the inside wall of the container.
As for the method for the lining formation, there has been known a repair method and a replacement method. According to the repair method a fresh refractory lining is applied on the surface of an old lining, and according to the replacement method the old lining is removed and a fresh refractory lining is formed.
Among the metallurgical container to be applied with refractory lining, there are non-movable containers, such as a fixed trough provided on the blast furnace casting floor, and movable containers, such as an exchangeable trough and a tundish. Therefore, it is desirable the refractory lining can be applied to various types of containers.
For actual practice of the vibration-pressing lining method, it is important that the mold can freely sink-down, and the thickness of the lining to be obtained is almost equal around the mold, or a desired thickness is obtained around the mold.
The present inventors have discovered that when a forming mold having a weight on its top is placed on the powder and granular refractory mix charged in the container and vibration is given to the mix, the mold is vibrated down into the refractory mix and sinks-down considerably before the refractory mix shows the thixotropic property. The depth or distance of sink-down of the mold at this time varies depending on the condition of the refractory mix charged in the container, and as the forming surface of the mold is curved as mentioned hereinafter the mold is not stable in its position so that there is a problem that the mold inclines.
Further, when a guide as disclosed in Japanese Pat. No. 48-17405 is used for guiding the mold, there is a problem that when the mold inclines and contacts the guide and the mold is restricted thereby in its sinking-down. In this case, if the mold is hammered on the portion contacting the guide, the mold is released, but the operation is hindered remarkably.
Therefore, the object of the present invention is to provide a lining apparatus which overcomes the above defects and meets with various requirements.
The present invention will be described in details referring the attached drawings.